Engine starter

ABSTRACT

A device for applying a large torque to start a large engine. A member pivoting about the axis of a drive gear has an idler gear pivotally mounted on it which is in mesh with the drive gear so that when the member is rotated about the axis of the pinion gear, the idler gear is brought into contact with the fly wheel gear on the engine so that it can be turned by the drive gear to start the engine.

United States Patent Webb [ Sept. 12, 1972 [54] ENGINE STARTER v [72]Inventor: Paul D. Webb, Tioga, Pa. l6946 [73] Assignee: Fraser-WebbCorporation [22] Filed: Sept. 23, 1970 [21] Appl.No.: 74,695 g 52] Us;01. ..74/8, 123/179 F 51 1111.01. ..F0ln 7/08 58 Field of Search ..74/&123/179 F; 92/119 [56] References Cited UNITED STATES PATENTS 1,262,6664/1918 Heinze ..74/8 x 2,905,001 9/ 1959 Courtney et a1 ..74/8

6/ 1969 Meyer ..74/8 7/1912 Desmond ..92/l19 Primary Examiner-MiltonKaufman Attorney-John E. Wilson [57] ABSTRACT A device for applying alarge torque to start a large engine. A member pivoting about the axisof a drive gear has an idler gear pivotally mounted on it which is inmesh with the drive gear so that when the member is rotated about theaxis of the pinion gear, the idler gear is brought into contact with thefly wheel gear on the engine so that it can be turned by the drive gearto start the engine.

2 Claims, 2 Drawing Figures OFF 52 PATENTEDSEP 12 I972 ATTORNEY ENGINESTARTER BACKGROUND OF THE INVENTION which would be used to drive such apump isby necessity'large and powerful and therefore one which wouldrequire the application of a large torque to crank it.

Conventionally, several Bendix-type starters which engage with the flywheel ring gear are used to crank the engine.- I The engine, which isoften approximately l,0,000 I-l.P. .demands much of the starters andconsequently, they often fail mechanically.

SUMMARY OF THE INVENTION It is an object of the presentinvention toovercome drawbacks found in the prior art such as those discussed above.Accordingly, an idler gear in mesh with adrive gear moves so thatwhilecontinuously in mesh with the drive gear, it comes into mesh with anengine gear so that it can transmit torque to the engine gear and startthe engine.

' BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic view of amechanism made in accordance with the present invention; and

FIG. 2 is aschematic view of the pneumatic circuit within the scope ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 a portion ofa large engine is shown with an engine gearl2-which may be'a ring gearintegral with a fly wheel 14.

A starter mechanism 16 has a drive gear 18 fixed on a shaft 20 which maybe turned by means of gas under pressure acting on a positivedisplacement helical lobe screw type expander or other means forexerting sufficient torque. Mounted for pivotal movement about the shaft20 is a member 22 which-is pivotally connected at one end 214 to an endof a piston rod 26 of a power cylinder 28. The power cylinder 28, whichmay be of the double acting pneumatic type is pivoted at the cylinderend 30 to the frame 32 of the starter apparatus. Rotatably mounted atthe other end of the member 22 is a shaft 36 upon which is mounted anidler gear 38 whichfis in mesh with the drive gear 18.

The member 22 can be rotated about the shaft 20 by the power cylinder28. Thus, if the cylinder pressure were to move the piston rod 26downward, the idler gear would be moved upward, the end of its travelbeing the position shown in phantom in FIG. 1. Similarly, if the rod 26were then to be moved upward the idler gear 38 would move downward. Whenthe engine 10 is running, and the engine fly wheel gear 12 is turning,the idler gear 38 is held in the position shown in phantom in FIG. 1.When the present starter is cranking the engine, the idler gear is inthe position shown in full line in FIG. 1. In this position, the member22 engages, at a location adjacent to the shaft 36, a saddle 40 whichextends downward and is preferably connected with a foundation under thepresent starter 16.

The member 22 includes a downwardly extending projection 42 which, whenthe idler gear is in the full line position, engages a limit valve orlimit switch 44 for reasons which will appear presently.

Ithas been pointed out previously that when the engine 10 is running theidler gear 38 is in the phantom line position. When the engine, 10 isnot running and it is desired to start it, the power cylinder 28 isactuated to raise the piston rod 26 and rotate the member 22 about theshaft 20. While this taking place, the idler gear 38 is rotating aboutits own axis in a counterclockwise direction because it is in mesh withthe drive gear 18. When the idler gear 38 contacts the ring gear 12 itwill rotate about its own axis in a clockwise direction to rotate thedrive gear slightly. This action greatly lessens any possibility of theidler gear becoming hung up" on the fly wheel gear. Even if it did, thecylinder 28 will not exert enough force to damage the gear teeth.

When the member 22 contacts the saddle 40 it will no longer rotate andthe drive gearis then made to rotate to turn the idler gear 38 andthefly wheel gear 12. The engine gear 12 exerts a large reaction forceon the idler gear 38 and consequently the resultant force on the idlergear 38 will be large and in a downward direction. The saddle willtransmit this force to the foundation so that the starter mechanism 16will not be damaged.

When the engine 10 is tired and the fly wheel ring gear 12 begins toturn rapidly the gear 38 will be thrown upwardly so that the member 22will rotate about the shaft 20 until the idler gear 38 is in its phantomline position. This action occurs because after the engine fires itdrives the starter to reverse the direction of the resultantforce on theidler gear. Preferably the cylinder pressure is, at this time reversedto urge the rod 26 downward and thereby aid in the disengagement of thestarter 16. Because the idler gear 38 is moved upwardly by the ring gear12, the teeth on each of these gears always move at the same linearspeed until the idler gear disengages. This prevents any damage to theteeth.

In FIG. 2, a hydraulic system 50 which is suitable for incorporation inthe present invention, is diagramatically shown. The gas cylinder 28along with the member 22, engine gear 14, drive gear 18, idler gear 38and the limit switch 44 which have already been mentioned are all shown.

When it is desired to start the engine 10 a control valve 52, which ispreferably a four-way valve, is actuated to the on position as shown inFIG. 2. Gas under pressure will flow from gas source 54 through thefourway valve, pneumatic lines 56 and 58 through a second control valve60, which may be a spring return valve, the pneumatic lines 62 and 64and through the pneumatic limit switch 44 to the blow-off 66. The springreturn push button 68 is then pushed inwardly to close the valve andthereby prevent the gas from reaching the blow-off 66 so that the gaswill flow through the pneumatic line 70 to the gas cylinder 28.Pressurizing the gas cylinder 28 will cause it to rotate the member 22to bring the idler gear 38 into the position shown in full line inFIG. 1. The projection 42 will therefore engage and actuate thepneumatic limit switch 44 to eliminate blow-off at 66. This occurs inonly a short time after the button 68 is depressed. The operator maythen allow the button 68 to return to its normal position withoutrelieving pressure at the lines 62 and 70 so that the cylinder 28 willremain pressurized. When the spring return valve is opened by releasingthe button 68 gas under pressure will flow through the line 62 and aline 72 to a diaphragm 74 of a starter gas supply valve 76 whichcontrols flow of gas to the starter. When the diaphragm 74 becomespressurized it actuates a rod 78 which opens the supply valve 76. Thisallows gas under pressure to energize the starter which rotates thedrive gear 18.

When the engine fires the four-way valve 52 is turned to the offposition to rotate the valve core ninety degrees so that gas from thecylinder can pass through lines 70 and 56 to be blown off at 80 and forgas under pressure to pass through line 82 to the top of the cylinderand its piston. As already explained, the engine after it. starts, runsthe starter and since the member 22 is no longer held in position by thecylinder 28 the member will be thrown upwardly, that is in a clockwisedirection by the force of the engine gear 12 and the cylinder whichmoves the rod 26 downwardly. This, of course, will cause the idler gear38 to disengage from the ring gear 12 and assume the phantom lineposition shown in FIG. 1.

It has already been explained that the present invention is useful inengines which are. used to pump gas in gas lines. In such environments,gas under pressure is available and can be used in the pneumatic system50. Of course, if air or any other suitable fluid were available undersufficient pressure it could be used and function satisfactorily.

The present engine starter has several inherent advantages which havenot been discussed thus far. For one, if any of the pneumatic lines wereto rupture, the starter could not be engaged. If the rupture occurredafter it was engaged it would disengage. It is also to be noted that thestarter will not operate until the pneumatic limit switch 44 is closed,that is until after the member 22 is moved fully into position. Further,two valve operations namely actuation of the four-way valve 52 andspring return valve 60 are necessary to engage and operate the presentstarter. However, to disengage the starter, it is only necessary toactuate either one of those valves. It will be readily apparent how eachof these features makes the present starter extremely safe.

The foregoing describes but one embodiment of the present invention. Oneof ordinary skill in the art will appreciate that the describedembodiment may be modified without exceeding the scope of the presentinvention as defined in the following claims.

I claim:

1. A device for starting an engine having an engine gear comprising adrive gear for transmitting torque and an idler gear, said idler gearbeing in mesh with said drive gear, a member pivotally mounted forrotation a out the axis of said drive e r, said idler ear bein pivotallyconnected with sai d member, a powe cylinder connected at one end ofsaid member so that it will rotate said member when said power cylinderis actuated so that the axis of said idler gear rotates about the axisof said drive gear while said idler gear meshes with said drive gear tobring said idler gear into mesh with said engine gear and to a positionsuitable for transmitting torque from said drive gear to said enginegear, said device further comprising a first control valve, a line fordirecting fluid under pressure coming from said control valve to saidpower cylinder, a second control valve, a line for directing fluidpressure from said first control valve to said second control valve, astarter supply valve and a limit valve, said starter supply valveadapted to supply fluid under pressure to rotate said'drive gear, saidlimit valve adapted to direct fluid to a blow-off when open and beingpositioned so as to be closed by said member when said idler gear is insaid position suitable for transmitting torque from said drive gear tosaid engine gear, lines for directing fluid pressure from said secondcontrol valve to said limit valve and said starter supply valve, wherebywhen said first control valve is actuated to direct fluid to said powercylinder, fluid will flow through said second control valve and saidlimit valve to blow-ofl', but when said second control valve is closed,said fluid will flow into an end of said power cylinder to rotate saidmember and close said limit valve so that said second control valve canbe opened to allow fluid to flow to said starter supply valve.

2. The device defined in claim 1 wherein said power cylinder is a doubleacting cylinder and said first control valve can be activated to supplyfluid to the other end of said cylinder to rotate said member into theposition where said idler gear is out of contact with said engine gearand to direct fluid from said one cylinder end to blow-off.

1. A device for starting an engine having an engine gear comprising adrive gear for transmitting torque and an idler gear, said idler gearbeing in mesh with said drive gear, a member pivotally mounted forrotation about the axis of said drive gear, said idler gear beingpivotally connected with said member, a power cylinder connected at oneend of said member so that it will rotate said member when said powercylinder is actuated so that the axis of said idler gear rotates aboutthe axis of said drive gear while said idler gear meshes with said drivegear to bring said idler gear into mesh with said engine gear and to aposition suitable for transmitting torque from said drive gear to saidengine gear, said device further comprising a first control valve, aline for directing fluid under pressure coming from said control valveto said power cylinder, a second control valve, a line for directingfluid pressure from said first control valve to said second controlvalve, a starter supply valve and a limit valve, said starter supplyvalve adapted to supply fluid under pressure to rotate said drive gear,said limit valve adapted to direct fluid to a blow-off when open andbeing positioned so as to be closed by said member when said idler gearis in said position suitable for transmitting torque from said drivegear to said engine gear, lines for directing fluid pressure from saidsecond control valve to said limit valve and said starter supply valve,whereby when said first control valve is actuated to direct fluid tosaid power cylinder, fluid will flow through said second control valveand said limit valve to blow-off, but when said second control valve isclosed, said fluid will flow into an end of said power cylinder torotate said member and close said limit valve so that said Secondcontrol valve can be opened to allow fluid to flow to said startersupply valve.
 2. The device defined in claim 1 wherein said powercylinder is a double acting cylinder and said first control valve can beactivated to supply fluid to the other end of said cylinder to rotatesaid member into the position where said idler gear is out of contactwith said engine gear and to direct fluid from said one cylinder end toblow-off.